全文获取类型
收费全文 | 269046篇 |
免费 | 21100篇 |
国内免费 | 4817篇 |
专业分类
耳鼻咽喉 | 1656篇 |
儿科学 | 5461篇 |
妇产科学 | 5141篇 |
基础医学 | 27509篇 |
口腔科学 | 5242篇 |
临床医学 | 41140篇 |
内科学 | 33815篇 |
皮肤病学 | 2951篇 |
神经病学 | 16184篇 |
特种医学 | 7352篇 |
外国民族医学 | 2篇 |
外科学 | 21214篇 |
综合类 | 30406篇 |
现状与发展 | 21篇 |
一般理论 | 74篇 |
预防医学 | 33114篇 |
眼科学 | 2671篇 |
药学 | 31126篇 |
223篇 | |
中国医学 | 13635篇 |
肿瘤学 | 16026篇 |
出版年
2024年 | 710篇 |
2023年 | 5394篇 |
2022年 | 8996篇 |
2021年 | 12420篇 |
2020年 | 11429篇 |
2019年 | 11117篇 |
2018年 | 10749篇 |
2017年 | 10917篇 |
2016年 | 10597篇 |
2015年 | 9926篇 |
2014年 | 13603篇 |
2013年 | 18571篇 |
2012年 | 13829篇 |
2011年 | 15792篇 |
2010年 | 10545篇 |
2009年 | 10772篇 |
2008年 | 11942篇 |
2007年 | 12987篇 |
2006年 | 11998篇 |
2005年 | 10798篇 |
2004年 | 9237篇 |
2003年 | 8041篇 |
2002年 | 6280篇 |
2001年 | 5647篇 |
2000年 | 4829篇 |
1999年 | 4125篇 |
1998年 | 3280篇 |
1997年 | 3239篇 |
1996年 | 2956篇 |
1995年 | 2543篇 |
1994年 | 2423篇 |
1993年 | 2007篇 |
1992年 | 1789篇 |
1991年 | 1694篇 |
1990年 | 1464篇 |
1989年 | 1191篇 |
1988年 | 1108篇 |
1987年 | 1017篇 |
1986年 | 937篇 |
1985年 | 1395篇 |
1984年 | 1122篇 |
1983年 | 874篇 |
1982年 | 884篇 |
1981年 | 709篇 |
1980年 | 704篇 |
1979年 | 527篇 |
1978年 | 323篇 |
1977年 | 288篇 |
1976年 | 275篇 |
1975年 | 197篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
MONIQUE DAVRIL MIREILLE GUAY KIA-KI HAN FRANCOIS LAMY 《Chemical biology & drug design》1987,29(1):68-77
This report describes the use of photolysis and ozonolysis as a means of achieving complete cleavage of the pyridinium ring of (iso)desmosine in crosslinked elastin peptides. Although photolysis leads to the opening of the ring with concomitant formation of lysine, the peptide chains remain attached. Subsequent ozonolysis is able to completely achieve the cleavage of the rest of the ring skeleton, thus leading to the separation of the peptide chains. Formation of new amino acids, i.e. α-aminoadipic and glutamic acids, is emphasized. Localization of these amino acids within the released peptides should be of help in structural investigations on the crosslinking zones involving either isodesmosine or desmosine. However, other amino acids such as tyrosine and phenylalanine are sensitive to this procedure and side reactions occur which are responsible for peptide bond cleavage with the formation of breakdown products. 相似文献
102.
The H-reflex of 120 soleus motoneurons was recorded using fibre EMG. The recovery profile of these motoneurons was studied during monitoring surface H-reflex records in 28 adult subjects. The spectrum of motoneurons tested was homogeneous with two extremes of neurons having different characteristics. A motoneuron population (forming about 69% of our sample) had a high threshold level for electrical stimuli, short recovery time, and short recovery fringe time (called type A). A second population of motoneurons (forming about 20-30% of our sample) had a low threshold level for electrical stimuli, long recovery fringe time (called type B). During an isometric muscle contraction every motoneuron showed an early shift in recovery time (i.e. each had a shorter recovery time) with shortened recovery fringe time. These changes were larger for motoneurons type B than motoneurons type A. With paired identical electrical stimuli of varying interstimulus intervals a motoneuron may fire in response to the conditioning and test stimuli giving an H2, but not in response to both stimuli. This occurred for interstimulus intervals of 4-11 ms. A strong inhibition period was recorded with interstimulus intervals of 12-80 ms in which all motoneurons did not show any recovery. Most motoneurons recovered in orderly fashion between 80 and 300 ms of interstimulus interval, and this recovery coincided with the fast recovery recorded in surface H-reflex. All motoneurons were recovered by 3000 ms of interstimulus intervals. These findings emphasize the importance of eliciting the H-reflex every 3-5 s in H-reflex methodology in order to be assured that all excited motoneurons have been recovered. 相似文献
103.
通过具体的实验数据,讨论在药代动力学实验中如何加入曲线下面积(AUC)的计算,以帮助学生理解并掌握这一概念;在实验室设置不同剂量组,给药后比较剂量与浓度是否呈等比例关系,以此加深学生对于一级动力学消除及其临床意义的理解。 相似文献
104.
目的探讨群体损伤院前急救转运存在的风险与防范对策。方法通过547例群体损伤转运,分析影响安全转运存在的风险,正确评估和判断风险,制定有效的防范措施和对策。结果 547例伤员安全转运入院治疗,入院率100%。结论预见转运存在风险,采取有效防范对策,是确保成功转运的关键因素。 相似文献
105.
106.
In this study we consider the process of the clinical encounter, and present exemplars of how assumptions of both clinicians and their patients can shift or transform in the course of a diagnostic interview. We examine the process as it is recalled, and further elaborated, in post-diagnostic interviews as part of a collaborative inquiry during reflections with clinicians and patients in the northeastern United States. Rather than treating assumptions by patients and providers as a fixed attribute of an individual, we treat them as occurring between people within a particular social context, the diagnostic interview. We explore the diagnostic interview as a landscape in which assumptions occur (and can shift), navigate the features of this landscape, and suggest that our examination can best be achieved by the systematic comparison of views of the multiple actors in an experience-near manner. We describe what might be gained by this shift in assumptions and how it can make visible what is at stake for clinician and patient in their local moral worlds—for patients, acknowledgment of social suffering, for clinicians how assumptions are a barrier to engagement with minority patients. It is crucial for clinicians to develop this capacity for reflection when navigating the interactions with patients from different cultures, to recognize and transform assumptions, to notice ‘surprises’, and to elicit what really matters to patients in their care. 相似文献
107.
Further evidence of dopamine transporter dysregulation in ADHD: a controlled PET imaging study using altropane. 总被引:4,自引:0,他引:4
Thomas J Spencer Joseph Biederman Bertha K Madras Darin D Dougherty Ali A Bonab Elijahu Livni Peter C Meltzer Jessica Martin Scott Rauch Alan J Fischman 《Neuropsychopharmacology》2007,62(9):1059-1061
BACKGROUND: The dopamine transporter (DAT) is known to be a key regulator of dopamine, and recent studies of genetics, treatment, and imaging have highlighted the role of DAT in attention-deficit/hyperactivity disorder (ADHD). The findings of in vivo neuroimaging of DAT in ADHD have been somewhat discrepant, however. METHOD: Dopamine transporter binding was measured using a highly selective ligand (C-11 altropane) and positron emission tomography (PET). The sample consisted of 47 well-characterized, treatment-na?ve, nonsmoking, non-comorbid adults with and without ADHD. Additionally, control subjects had few symptoms of ADHD. RESULTS: Results showed significantly increased DAT binding in the right caudate in adults with ADHD compared with matched control subjects without this disorder. CONCLUSIONS: These results confirm abnormal DAT binding in the striatum of adults with ADHD and provide further support that dysregulation of DAT may be an important component of the pathophysiology of ADHD. 相似文献
108.
1 The internal anal sphincter (IAS) has a spontaneous tone and is the main contributor to the maintenance of faecal continence. The spontaneous resting tone exhibited by the sphincter can be modified by neurotransmitters from the autonomic and enteric nervous systems. 2 In this review, the influence of the sympathetic and parasympathetic nervous systems on IAS tone are discussed and the putative roles of nitric oxide, carbon monoxide, vasoactive intestinal peptide and adenosine triphosphate in non‐adrenergic non‐cholinergic transmission are considered. 3 Faecal incontinence is a common condition that places a heavy financial burden on the health service and severely affects patients’ quality of life. Resting anal pressure is reduced in patients with faecal incontinence and agents that increase sphincter tone tend to relieve symptoms. The results of clinical studies of the use of phenylephrine to treat faecal incontinence are reviewed. 4 It is concluded that the IAS is a potential target for drug development for the treatment of faecal incontinence. 相似文献
109.
目的探索一种适合ICU护理工作特点的管理模式,提高管理效应。方法用护理工作量、ICU护理质量标准奖惩考核、职称系数三部分综合考评护理工时,与护士的绩效工资分配直接挂钩。结果护理工时量化法实施后,护理质量考核评分,患者?医生对护理质量满意率显著高于实施前(P〈0.05,P〈0.01)。结论护理工时量化绩效分配克服了经验式管理的弊端,建立了有效的激励机制,体现了多劳多得、优劳优得的分配原则,挖掘了护理人员的自身潜力,提高了护理质量。 相似文献
110.